Conventionally, proposed is an electrical power load leveling system which presents a time period where the power supply load of the electric power company is lowest in the day, and urging the respective utility customers to use electrical power during that time period (for instance, refer to Patent Literature 1).
In the foregoing electrical power load leveling system, it is described that the bottom electrical power of the power demand can be increased by presenting the time period (electricity usage recommended time) where the power supply load is the lowest in the day, and urging the respective utility customers to use electrical power during that time period. Moreover, it is further described that the reduction in the peak electrical power can also be expected, and the overall leveling of the power supply load can be achieved.
Moreover, it is further described that, as a result of leveling the load, this will lead to the electric power company being able to cut costs required for controlling the electric-generating capacity of the power supply in accordance with the power demand and, therefore, in addition to presenting the electricity usage recommended time, if a discount of the electricity charge is also offered during that time, it is expected that the electrical power users as the utility customers will intentionally use electrical power which is inexpensive during that time, and the leveling of power demand can be performed even more effectively.
As one example, in households, electrical water heaters and heat pump water heaters that boil water based on late-night electricity contracts and time period-based electric light contracts for leveling the daily power demand are already in widespread use. Hot water that was boiled using inexpensive electrical power of late night of the previous day (for example, from 11 PM to 7 AM) is stored in a hot water tank, and this hot water is used for meals, showers and bathing during the day, morning or night. Consequently, the power demand for boiling water is shifted to the time period of late night of the previous day.
These electrical water heaters and heat pump water heaters that are compatible with late-night electrical power have a clock means build therein, and starts the water-boiling operation upon reaching the time that was set in advance in the contract with the electric power company. In other words, these electrical water heaters and heat pump water heaters perform reservation operation at the pre-set operation start time (or operation termination time) on a daily basis.
In the future, it is considered that natural energy generation systems such as solar power generation systems and wind power generation systems will become widespread, and it is anticipated that, with these natural energy generation systems, the electric-generating capacity will change considerably depending on the weather and time.
Such being the case, technology for controlling the power demand will become even more important in the future. In addition to the conventional system of leveling the power demand and consequently controlling the electric-generating capacity, it is considered that a new system capable of controlling the power demand in accordance with the fluctuating electric-generating capacity will become required.
For example, the electric power company will be able to control the power demand according to the fluctuating electric-generating capacity by varying the electricity charge according to the fluctuating electric-generating capacity, and reducing the electricity charge when the electric-generating capacity is great and increasing the electricity charge when the electric-generating capacity is small.
Thus, proposed is an electrical equipment control system for controlling an electrical equipment via a home server (for instance, refer to Patent Literature 2). This control system comprises a home service which controls the electrical equipment by comparing the operating conditions of a plurality of electrical equipment and pre-stored conditions and calculating the ideal operation pattern, and an electrical equipment that is operated based on the ideal operation pattern according to the control of the home server.
In addition, with this control system, the electricity charge menu provided from the electric power company (electrical power supplier) is stored in home server so that the electrical equipment will be operated during the time period offering an inexpensive electricity charge as the ideal operation pattern, compares and computes this with the pre-input operating conditions, and operates the washer-drier, rice cooker, hot water dispenser and the like during the time period offering an inexpensive electricity charge.
Meanwhile, in areas where the use of solar power generation systems and wind power generation systems is widespread, there are countries that are adopting the real-time pricing system.
While a late-night electricity contract reduces the electricity charge during a given time period from 11 PM to 7 AM on a daily basis, in real-time pricing, the electrical power charge fluctuates in real-time in accordance with the electric-generating capacity of the solar power generation system or the wind power generation system, and the electricity charge will vary from day to day even during the same time period.
For example, electricity charge information (table showing the time period and electricity charge) in which the electricity charge is increased or decreased hour to hour is distributed from the electric power company to the utility customers. The frequency of distributing the electricity charge information is, for example, as follows: the electricity charge information of the following day is distributed on the current day. Otherwise, the electricity charge information of the afternoon of the current day is distributed during the morning of the current day. The user operates the electrical equipment by referring to this electricity charge information.
Nevertheless, since foregoing Patent Literature 1 does not give any consideration to this real-time pricing, there is a possibility that the user's convenience will be impaired if the household appliance is to be operated upon selecting the time period offering an inexpensive electricity charge based on the electricity charge information or the electricity charge menu provided by the electric power company.
For example, the electricity charge can be reduced by operating the electrical equipment during the time period offering an inexpensive electricity charge as in Patent Literature 1. When this system is adapted to the electricity charge information which frequently changes as with real-time pricing, the operation time of the electrical equipment will change each time the time period offering an inexpensive electricity charge changes. Consequently, there is a possibility that the user will not know when the operation will finish.
For instance, with a clothes washer-drier, there may be cases where the drying is finished sooner than the user had expected, whereby the fluffiness of the clothes may be lost or, with a rice cooker, there may be cases where the cooking of the rice is finished sooner than the user had expected, and the flavor of rice may deteriorate while the rice is being kept warm.